Mucosa-associated lymphoid tissue (MALT) lymphoma

2005-12-01   Gianluigi Castoldi , Antonio Cuneo 

1.Hematology Section, Department of Biomedical Sciences, University of Ferrara, Corso Giovecca 203, Ferrara, Italy

Clinics and Pathology


MALT lymphoma is the extra-nodal presentation of marginal zone B-cell lymphomas (MZBCL)

Phenotype stem cell origin

The morphologic and phenotypic characteristics of malignant cells correspond to those of lymphocytes belonging to the marginal zone, harbouring hypermutated IgV genes with the following immunophenotype: pan-B+; CD5-/+; CD10-; CD23-; CD11c+/-; cyIg +(40% of the cells), sIgM+ bright; sIgD-


The incidence of extra-nodal MZBCL of MALT type in western countries is approximately 7% of all NHL diagnosed by histologic examination.


  • Extra-nodal MZBCL of MALT type is an indolent disease involving most often the stomach, where it usually follows chronic gastritis due to Helicobacter pylori (HP) infection. The disease may also localize in the lung, the thyroid the salivary gland and in the orbit, where an association was documented with Chlamydia Psittaci infection
  • AS with other clinicopathological forms of MZBCL (i.e. splenic MZBCL and nodal MZBCL) transformation into high grade lymphoma may occur.
  • Pathology

    The tumour consists of a cytologically heterogeneous infiltrate including centrocyte-like cells, monocytoid B-cells small lymphocytes and plasma cells. Large cells and/or blast-like cells may be present. Typically, lymphoepithelial lesions are seen in the stomach.


    Low grade MALT with limited disease involving the stomach is usually HP+ and respond to eradication of the HP infection. Cases presenting at a more advanced stage or with transformation into high grade lymphoma require single-agent or multi-agent chemotherapy. Rituximab (anti-CD20 monoclonal antibody) is an effective treatment. Gastrectomy is indicated in non-responding patients.


    The patients usually have prolonged survival, as in other indolent lymphomas, but some cases may feature an aggressive disease.

    Result of the Chromosomal Anomaly


  • MALT1 overexpression and API2-MALT fusion confer constitutional NFkB activity. This, in turn, leads to enhanced proliferation and resistance to apoptosis by B lymphocytes.
  • BCL10 functions in conjunction with intracellular proteins (Carma1 and MALT1), producing the ubiquitination of NFkB inhibitor, leading to NFkB activation. These findings, along with the documented role of BCL10 in promoting survival of antigen-stimulated lymphocytes, suggest the IgH/BCL10 translocation may contribute to lymphomagenesis by enhancing BCL10 function.
  • Bibliography

    Pubmed IDLast YearTitleAuthors
    91668271997A clinical evaluation of the International Lymphoma Study Group classification of non-Hodgkin's lymphoma. The Non-Hodgkin's Lymphoma Classification Project.
    109397962000Translocation t(11;18) absent in early gastric marginal zone B-cell lymphoma of MALT type responding to eradication of Helicobacter pylori infection.Alpen B et al
    111465732001Molecular cytogenetic characterization of marginal zone B-cell lymphoma: correlation with clinicopathologic findings in 14 cases.Cuneo A et al
    109799682000Detection of t(11;18)(q21;q21) by interphase fluorescence in situ hybridization using API2 and MLT specific probes.Dierlamm J et al
    108459242000BCL10 gene mutation in lymphoma.Du MQ et al
    104068971999Frequent mutation of bcl-6 proto-oncogene in high grade, but not low grade, MALT lymphomas of the gastrointestinal tract.Gaidano G et al
    105778571999World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues: report of the Clinical Advisory Committee meeting-Airlie House, Virginia, November 1997.Harris NL et al
    155988102005MALT1 and the API2-MALT1 fusion act between CD40 and IKK and confer NF-kappa B-dependent proliferative advantage and resistance against FAS-induced cell death in B cells.Ho L et al
    103748861999Gastric low-grade MALT lymphoma, high-grade MALT lymphoma and diffuse large B cell lymphoma show different frequencies of trisomy.Hoeve MA et al
    111973612001Resistance of t(11;18) positive gastric mucosa-associated lymphoid tissue lymphoma to Helicobacter pylori eradication therapy.Liu H et al
    109079432000The product of the t(11;18), an API2-MLT fusion, is an almost exclusive finding in marginal zone cell lymphoma of extranodal MALT-type.Maes B et al
    156684682005Clinical activity of rituximab in gastric marginal zone non-Hodgkin's lymphoma resistant to or not eligible for anti-Helicobacter pylori therapy.Martinelli G et al
    93072771997The t(11;18)(q21;q21) chromosome translocation is a frequent and specific aberration in low-grade but not high-grade malignant non-Hodgkin's lymphomas of the mucosa-associated lymphoid tissue (MALT-) type.Ott G et al
    145743352004Primary pulmonary MALT lymphomas show frequent and heterogeneous cytogenetic abnormalities, including aneuploidy and translocations involving API2 and MALT1 and IGH and MALT1.Remstein ED et al
    157037842005T(3;14)(p14.1;q32) involving IGH and FOXP1 is a novel recurrent chromosomal aberration in MALT lymphoma.Streubel B et al
    158789762005Bcl10 can promote survival of antigen-stimulated B lymphocytes.Tian MT et al
    162040122005Long-term follow-up of gastric MALT lymphoma after Helicobacter pylori eradication.Wündisch T et al
    94507841998B-cell lymphoma of MALT type: a review with special emphasis on diagnostic and management problems of low-grade gastric tumours.Zucca E et al


    Atlas Image
    t(11;18)(q21;q21) FISH - Courtesy Charles Bangs, Ilana Galperin


    Gianluigi Castoldi ; Antonio Cuneo

    Mucosa-associated lymphoid tissue (MALT) lymphoma

    Atlas Genet Cytogenet Oncol Haematol. 2005-12-01

    Online version:

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